Inside the mysterious Yamal sinkhole 'crater' in Siberia

Andrei Plekhanov, a senior researcher at the Scientific Research Centre of the Arctic, stands beside the sinkhole discovered in the Yamal peninsula in Russia's far northern state of Siberia. "I've never seen such craters anywhere on Yamal, where I've been," explains Andrei. "And I've never heard my colleagues talk of anything similar."Picture: AP